Spark plug



A. A. MELLBLOM.

SPARK PLUG. APPLICATION FILED AUG.20. l9l8.

Patented Aug. 8, 1922.

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SPARK PLUG.

Specification of Letters Patent.

Patented Aug. 8, 1922.

Application filed August 26, 1918. Serial No. 251,370.

T all whom it may cancer-n:

Be it known that I, ADoLPH A. MELLBLOM, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Spark Plugs, of whichthe following is a full, clear, concise, and exact description,reference being bad to the accompanying drawings, forming a part of thisspecification.

The invention relates to spark plugs and has for its object theprovision of means whereby oil and other carbon producing elements areprevented from reaching the electrode of the plug, and thereby keep samedry and thus insure a spark which will properly ignite the explosivemixture in the cylinders of the engine.

It is a further object of the invention to design and arrange the partsso that the carbon producing elements will be directed towards the shellor ground side of the plug instead of towards the electrode therebypreventing the carbon producing elements from reaching the interior ofthe shell to interfere with the proper operation of the plug.

The invention has as an additional object the production of these andother advantages in a simple. and expeditious manner, all of which willbe explained and more readily understood when read in conjunction withthe accompanying drawings in which- Fig. 1 is an elevation of a sparkplug having one form of the invention applied thereto;

Fig. 2 is a. vertical section of the plug shown in Fig. 1; i

Fig. 3 is a section taken on line 3, 3 of Fi 2;

ig. 4 is a sectional view of the lowermost portion of a plug, having amodified structureapplied thereto; and

Fig. 5 is a top plan view of another structure which may be applied toan end of the electrode.

In the embodiment of the invention as shown in the drawings Icontemplate the use of the usual shell having the flat faced portions 11the exteriorly screw threaded portion 12 and the interiorly threadedportion 13 to receive the clamping nut 14. A porcelain insulator 15 isprovided with the enlarged portion 16 and the reduced extremity 17 whichterminates a suitable distance above the lowermost end of the shell 10.

Gaskets 18 and 19 are provided to hold the compression and prevent itsescape between the parts forming the plug. An electrode 23 is mounted inthe insulator 15 and is provided with the set and clamping nuts 21 and22 respectively. Upon the lowermost end of the elect-rode is arrangedthe disc shaped enlargement 23 which is of a weight suflicient towithstand a high degree of heat, the under side of which is providedwith the deflecting surface 24. This disc shaped member isarranged asuitable distance below the lowermost extremity of the shell 10 and isillustrated as being of a slightly less dimension than the bore orchamber 25 of the shell 10. This relative difference in dimension isprovided for the purpose of permitting any oil which might find its wayto the interior of the chamber 25 to pass without touching the disc. indropping from the interior of the shell 10. One of the objects ofproviding this distance between the lowermost extremity of the porcelaininsulator 15 and the top of the enlargement 23 is to prevent thepossibility of causing a short circuit bet-ween the disc 23 and theshell 10 by the accumulation of oil upon the porcelain and between thedisc and the end of the insulator. The relative position and approximatedistances between the lowermost end of the shelllO, the lowermostextremity of the insulator 15, the disc 23 and the shape of thelowermost face of the disc, co-operate with each other to prevent oilfrom reaching the electrode 20, keeping it dry and insuring a sparkacross the space between the disc 23 and the lowermost end of the shell10.

It is evident that the shape of the lowermost face of the member 23 willdeflect any oil striking it away from the lowermost end of the shell 10.also any oil striking this end of the shell will drop therefrom withouttouching the member 23. It is further evident that should any of the oilfind its way between the uppermost face of the disc 23 and the lowermostface of the shell 10 that it will strike the walls of the extremity ofthe insulator 17 and not reach the lowermost end of the electrode 20.this will conse- WVhat I claim and desire to cover by Letters Patent is:

A spark plug having a shell and an electrode having a member securedthereto, said member being arranged with respect to the shell to permita spark to occur between it andthe shell, said member having aconcaveconoidal deflecting surface.

In witness whereof, I hereunto subscribe my name this 21st day ofAugust, A. D. 1918.

ADOLPH A. MELLBLOM.

